Passengers will continue to pass through machines that display a generic outline of the human body, raising fewer privacy concerns.

The TSA move came after Rapiscan, the manufacturer of the 174 so-called “backscatter” machines, acknowledged it could not meet a congressional-ordered deadline to install privacy software on the machines.

“It is big news,” said Marc Rotenberg, executive director of the Electronic Privacy Information Center. “It removes the concern that people are being viewed naked by the TSA screener.”

In 2004 and 2005, the TSA at first dismissed privacy concerns, then sought to address them by placing TSA officers viewing the scanner imagery in remote locations, away from the passenger being screened. They also gave passengers the right to an alternative screening — a pat down.

But those solutions failed to appease privacy groups and some members of Congress, who felt both alternatives could be abused.

But while manufacturers of the less-intrusive “millimeter wave” machines found ways to use ATR software, backscatter machines have not.

This week, the TSA announced it is ending its contract with Rapiscan “due to its inability to deploy non-imaging ATR software.”

“By June 2013 travelers will only see machines which have ATR that allow for faster throughput. This means faster lanes for the traveler and enhanced security,” the TSA said in a statement.

The TSA could allow backscatter machines in the future if the company develops the required software, the TSA said.

Currently, the TSA uses the 174 backscatter machines in 30 airports, and has another 76 units in storage. It uses millimeter wave machines in 170 airports.

The decision to remove the backscatter machine will make moot, at least temporarily, travelers’ concerns about the health effects of the machines. Backscatter machines use X-rays, while millimeter wave machines use radio waves.

The TSA has long maintained both machines are safe, but recently signed an agreement with the National Academy of Sciences to study the scanners. The study will continue even though the machines are being pulled, the TSA said, because they could be reintroduced in the future.